The electronic distribution and consumption of electronic books is changing the nature of publishing. Books can now be published and republished with very little expense. In many cases, books can be published by simply submitting them electronically to an electronic distribution service.
However, electronic distribution services face a challenge in organizing and indexing the many book submissions that are received. This challenge is complicated by the fact that various versions of the same book may often be submitted. This may happen where a publisher offers a book in different versions, revisions, or editions. For example, an initial book offering may be followed by a version containing corrections and revisions. As another example, a subsequent edition of a book may contain a special forward or other front/back matter. As yet another example, different publishers or sources may submit various versions of the same book, particularly where the book is in the public domain, or when publishing rights are held by different publishers in different jurisdictions.
Electronic book submissions may be accompanied by metadata such as title, authorship, and other information, and this information can sometimes be compared to determine whether two submissions are the same book. However, metadata such as this is not always definitive. Titles, for example, may not always be sufficient because they may not be entirely consistent from one version to another, and because different books may have similar titles. Furthermore, supplied metadata varies in its completeness and accuracy.